Dead Battery, High Voltage? - Ducati Monster Forums: Ducati Monster Motorcycle Forum

erik822 · 10-30-2007, 11:38 AM

Went to start the Monster on Sunday. Just clicked. Didn't turn over at all. Battery voltage was at 12.4, but dropped to 10.2 when I put a load on it (tried to crank the engine). I think that means the battery is on the way out. It had only been sitting for a week since it was used last. After jumpstarting the bike, I went for ride Sunday and the bike ran fine and restarted fine after sitting for an hour.

When I jumped the bike and read the voltage at my electric vest connector. It read 16.9volts@2000RPM (high idle).

So my questions are:
Should I get a new battery?
Does the high voltage mean the regulator is toast, or that a normal reading for 2000rpm with a low battery?
If I do need a regulator, how much should I expect to pay for one?

fasterblkduc · 10-30-2007, 05:42 PM

Check your voltage on the battery itself at about mid revs (around 5K RPM) It should read 14V. If it does not, then you may have a bad regulator.
If you do have 14v, then it's probably going to be the battery. Getting the full 14v, means that the charging system is working and the battery is the problem. The only exception would be somewhere else in the circuit like the battery cables, or a possible short that is draining the battery when the bike is not running. I've seen this issue with aftermarket electrical mods. You said that you had an electric vest connector? I am suspicious of that. Did the problem start soon after hooking that up?

Measuring the battery the way you did (at rest, and while cranking), is not going to tell you anything. Also measuring through the vest connector will not tell you anything about the charging system or the battery. So measure voltage at the battery.

Report back and let us know what you find...good luck

fasterblkduc · 11-05-2007, 12:19 PM

update?

erik822 · 11-07-2007, 10:02 AM

Got lazy. Jump started it this weekend (battery was dead again) and once it fired up I decided to just ride it, rather than spend the 15 extra seconds it would have taken to check the voltage. Pathetic, I know. I'll be checking it this weekend. I'll post the results at that time.

fasterblkduc · 11-07-2007, 10:20 AM

[laugh] I can relate. At least you're honest.

Do you have the immobilizer? Aftermarket electric mods don't get along with the immobilizer. I didn't mention before that the immobilizer is the reason that I suspect your electric vest plug in. I had an issue with something similar and the problem did not go away until I removed my circuit. I found out later that it was probably due to the immobilizer not accepting my added on circuit.

I'll be curious to see what you come up with.

erik822 · 11-10-2007, 09:34 PM

Went out to start the bike again today. Battery, once again, dead. Fired right up with a jumpstart. Checked the voltage at the battery: 14.5 volts.

So I decided to checked the voltage at the vest connector: 16 volts.

Since there wasn't any vest attached, that seemed weird to me. The connector is just a wire that hooks up to the battery. It's not a complete circuit. So I checked it again - this time I pushed the leads from the voltmeter into the connector harder. Then I got a better read: 14.5 volts.

From what I can tell that seems normal.

It turns out I have a battery that's on it's way out and I'm incompetent with a multi meter.

So that's it. I just need a battery. And a few more brain cells.
If only I hadn't wasted all those extra ones in college...